<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>
        *{
            margin: 0;
            padding: 0;

        }
        iframe{
            width: 1000px;
            height: 900px;
            border: 2px solid red;
        }
    </style>
</head>
<body>
<iframe src="" frameborder="0" name="321">
</iframe>
<a href="http://www.baidu.com" target="321">百度一下</a>
<a href="http://www.tamll.com" target="321">小米官网</a>
</body>
</html>